What would be the product of the reaction of 4-methyl pyridine with Ac2O/AcOH and PhCHO?

I'm really stuck on this. I'm guessing the pyridine will attack the anhydride and form an acyl pyridinium ion but I'm not sure where to go from there. If that reacts with AcOH I'll end up back with what I started with, so I figured it must react with the aldehyde some how. PhCHO has no enolisable H so I don't think this is an aldol reaction. Any help would be greatly appreciated.

To determine the product of the reaction of 4-methyl pyridine with Ac2O/AcOH and PhCHO, let's break down the steps in the reaction and consider the reactivity of the different compounds involved.

1. Ac2O/AcOH is a mixture of acetic anhydride and acetic acid. Ac2O is a strong electrophile due to the presence of the acyl (RCO) group and can react with nucleophiles.

2. In the first step, 4-methyl pyridine (which is a nucleophile) can react with Ac2O to form an acyl pyridinium ion. This acyl pyridinium ion is stabilized by resonance with the nitrogen atom and forms a reactive intermediate.

3. However, as you correctly noted, further reaction with AcOH would lead back to the starting material. Therefore, we look for another potential nucleophile in the reaction mixture.

4. PhCHO is benzaldehyde, which is an electrophile due to the presence of the carbonyl group. It does not have any enolisable hydrogens, so an aldol reaction is unlikely.

5. The acyl pyridinium ion can act as a nucleophile and attack the carbonyl carbon of benzaldehyde (PhCHO) in an electrophilic addition. This forms an addition product, which can further undergo rearrangement or elimination.

Considering the reaction conditions and the reactivity of the compounds involved, one possible product is N-(4-methylpyridin-1-yl)benzamide.

To verify this answer or explore other potential products, it's always helpful to consult available literature, such as organic chemistry textbooks or research articles, to see if similar reactions have been reported and to gain further insights into the likely outcome of the reaction.

Remember, organic chemistry reactions can sometimes have multiple possible products depending on different factors, so further experimental evidence or analysis may be necessary to definitively determine the product.